Method of preparing uranium deuteride



Oct. 26, 1948.

A. S. NEWTON METHOD OF PREPARING URANIUM ISEUTERIDE I Filed July 22,1944 Patented Oct. 26, 1948 METHOD OF PREPARING URANIUM DEUTERIDE AmosS. Newton,

United States of Ames, Iowa, assignor to the America as represented bythe United States Atomic Energy Commission Application July 22, 1944,Serial No. 546,179

7 Claims.

This invention relates to the production of compositions consisting ofor comprising uranium deuteride and is particularly related toproduction of uranium deuteride in a highly purified state.

In accordance with the present invention, I have provided uraniumdeuteride substantially free from other impurities or in a concentratedstate as a uranium hydride-deuteride composition in which the hydrogencontent is preponderantly heavy hydrogen and preferabl in which at least90 per cent of the hydrogen is heavyhydrogen. The production of thedeuteride is secured by re action of deuterium with metallic uranium andmust be conducted under conditions such that little or no deuterium islost. It has been found that this may be effectively performed in aclosed system in which deuterium oxide is introduced, and deuterium isgenerated from the deuterium oxide and directly used in the system toform the uranium deuteride. The process may be performed in a mannersuch that completion of the reaction may be automatically indicated asmore fully described hereinafter.

Difiiculty is frequentl encountered in effecting the reaction ofdeuterium with certain forms of uranium. Thus, when uranium powder isused the reaction is often difficult to control and may even occur withexplosive violence. On the other hand when sintered uranium powder isused the uranium deuteride forms as a coating and the reaction ceasesuntil the deuteride has been removed to expose a fresh uranium surface.In accordance with the present invention it has been found that many ofthe difiiculties may be avoided by use of massive or dense uranium metalwhich is free or substantially free from oxide parting planes in theinterior of the uranium mass. When such uranium is used, uraniumdeuteride is formed in a pulverulent state and crumbles and falls fromthe uranium body thereby continuously exposing freshuranium to thedeuterium. The reaction proceeds so long as metallic uranium is presentand the temperature of reaction is maintained.

The metallic uranium used in accordance with this invention may be ofhigh purity or may be mixed, contaminated or alloyed with othermaterials including tin, copper, bismuth, gold, silver or other metal.The uranium may be alloyed with these metals or merely physically mixedtherewith. Moreover the uranium may contain other substances so long asit is substantiall free from internal oxide parting planes. Such uraniumor at least the uranium content of ura- 2 nium mixtures has a meltingpoint not in excess of about 1200 C. and in consequence has a density ofabove 18 grams per cubic centimeter.

Oxide free uranium in massive state suitable for use as hereincontemplated ma be prepared by reduction of metallic uranium underconditions such that the uranium becomes molten and drains or stratifiesto form a molten pool of uranium from which the impurities separate as aslag layer. Upon solidification of the pool the uranium secured is denseand essentially massive. For example uranium tetrafluoride or similarhalide may be reacted with an alkaline earth metal such as magnesium orcalcium with consequent formation of an alkaline earth fluoride anduranium metal at a temperature sufiiciently high to melt the uranium andcause it to separate from the fluoride into a molten uranium pool.Alloys or mixtures of this uranium with other metals, particularlythose'in which the uranium is the prepoderant component may be treatedas herein contemplated.

The foregoing constitute the principal objects of the invention and Willbe more fully understood by reference to the specification and theaccomanying drawing which is a diagrammatic sectional view of apparatusfor carrying out the process.

The uranium deuteride produced in accordance with the invention can beconsidered to be an intermetallic compound between uranium and deuteriumhaving the approximate composition UDs. Analyses made on the basis ofweight gain upon formation of the compound indicate a slightly varyingdeuterium content depending upon the manner in which the uraniumdeuteride is treated. Adsorption of the deuterium by the uraniumdeuteride tends to increase the deuterium content of the compound.

Broadly, the process embodying the invention comprises forming uraniumdeuteride by bringing deuterium in gaseous form into contact withmassive uranium essentiall free from internal oxide parting planes attemperatures sufiiciently high to provide a reasonably rapid rate ofreaction of the deuterium and uranium. Preferably the process includespreparing deuterium in gaseous form, as by the reduction of deuteriumoxide, and then reacting such deuterium with uranium at elevatedtemperatures toform uranium deuteride, the reactions being carried outin a closed system.

The drawing illustrates one example of a suitable apparatus I, forproviding a closed system wherein gaseous deuterium is prepared andreacted with uranium. This apparatus includes a container for deuteriumoxide such as receptacle 2 containing deuterium oxide 3 in an amountsuificient to yield, by reduction of the deuterium oxide, the quantityof deuterium in gaseous form required for the formation of uraniumdeuteride by the subsequent reaction of the deuterium and uranium. Toincrease the vaporization of deuterium oxide 3 over that obtained atroom temperature, Water bath 4 is provided. Water bath 4, heated byconventional heating means, not shown, raises the temperature of thedeuterium oxide 3 above room temperature, as for example, to atemperature of approximately 30 C. The deuterium oxide in the form ofvapor admitted from receptacle 2 to the closed system i through.stopcock 6.

For passage of the deuterium oxide vapor, tube '1 extends fromreceptacle 2 into reduction chamber B which is of sufficient size tocontaina reducing agent 9. The reducin agent 9 may be iron, :zinc, orother material which will combine with (the oxygen of the,oleuteriumoxide te ror-m an oxide of -tl'le reducingiagent 9 andrelease thedeuterium in gaseous form. Metallic uranium has been foundtor-beparticularly suitable for this pwpose as it is highly reactiveavith deuterium oX-ide vapor and causes a substantially completereduction thereof. The reducing agent 9 is preferablyin a 'form such astoiiaverexposed a large surface area, as in the :form of .turnings 'orthe like, .and {is so arranged in reduction chamber .8

as to readily contact the .deuterium oxide vapor coming from. tube J.Where metallic. uranium is used as .a reducing agent, stable formationof uranium deuteride in the reduction chamber 8 is prevented bymaintaining the uranium at a high temperature.

, flhe reduction @chamber 8 is surrounded by heating means "M which, forexample, {may be of conventicnalelectric .ru r nace construction and inthe simplest dorm :maycornprise turn-ace casing l2 containing electricheating elements 1-3. Heating :means All is adapted to -maintainreduction ohambeiufi at a suitable temperature sufiicientlt high tocause the iron or' otherqmetal torreact with the deuteriurnwoxide toform deuterium, suehas, ior example, at 2a temperature between 600 QC.and 800 C., for the reduction of the deuterium oxide vapor by reducingagent 9. Heat ng means all includes suitable control means, not shown,

.fcr maintaining med-notion [chamber :8 at the desired temperatures.

The gaseous deuterium resultin ,zfrom zthereduction of the.deuteriumpxide :is conveyed from .re,duction--.c-hamber -8-into trap 46:by tube [4 which extends into the trap. The trap 1 I 6:1'emovesunred-.uced deuterium oxide vapor -.carried by the gasleous deuterium,the purification being eiiected by maintaining the trap atlowtemperatures, thereby causing condensation of any deuterium oxide--vapor present. Trap L6 is cooled by suitabletcool- .ing means suchasgfor example, solid carbon 1dioxide H and acetone :IB containedreceptacle 415. purified deuterium is conveyed .trom trap I16 intoreaction achamberlz through tube its-and stopcock 2-! Where it is :founddesirable to effect the :prepla-rationof uranium deuteride :by :thereaction 'of previously prepared deuterium and uranium meta'l'ortosupplement deuteriumpreparedin chainber-fl -supply tube 3-! maybeprovided for introducing previously prepared gaseous deuterium friom asource of gaseous deuterium, 'not shown, through tube 4:9 and intoreaction chamber 2-2. :Supplytube ,3 I may be opened-and .closedbytopcock 32. If the process comprises preparing gaseous deuterium andreacting such deuterium with uranium in the closed system I, stopcock 32is closed, thereby shutting ofi supply tube 3|. If the process includesreacting previously prepared deuterium with uranium in reaction chamber22, stopcock-2| may the closed tiQShutlOfi :supply tube lELand stopcockZ32 is opened, thereby :admitting previously prepared deuterium toreaction chamber 22 or deuterium may be supplied from both sources.

Reaction chamber 22 contains metallic uranium 23 in massive or densestate and free from internal oxide parting :planes with which thegaseous deuterium reacts to form uranium deuteride.

' Preferably, the uranium metal 23 is in a form presenting .a largesurface area, as in the form of turnings or the like. The reactionchamber 22 .is surrounded by heating means 24 such as a conventionalelectric furnace comprising casing .28 containing electric heatingelements 2 Heatin means-24 is adapted to maintain reaction chamberiZZ at.a suitable temperature, such as, for example, between 15.0" C.-and 400C, forlcausing a reasonably rapid rate of reaction between the gaseousdeuterium and :the metallic uranium. Heating means 24 includes suitableand conventional control means for ,-maintaining .reaction chamber 22 atthe desired temperature.

As it is desirable to .remove residual atmospheric oxygen from thesystem before carrying out theiprocess, reaction chamber 22 isprovidedwith outlet tube 2:8 which is "connected to .a conventional type ofmechanical exhaust means, not shown, capable of obtaining a vacuum inthe system of the order of .l millimeter mercury pressure and the systemisevacuated whilestopcock =9 is closed. After evacuation-stopcock 29 isclosed thereby closing the entire system.

, The various elementsof :the apparatus are 1 suitably formed of a.material, such as :heat resistant glass, stainless steel, ,glass linediron, etc., that withstands .elevatedtemperatures, resists corrosion,and does not contaminate-orzreact with the substances presentin the.system. Manometer 33 "or equivalent pressure indicating .means may beconnectedto the system on an extension .of tube 1 .to indicate visuallythe pressures developed during theprocess.

Where it is desiredlto obtain uranium deuteride by a process in whichpreviously prepared-deuterium .is reacted with uranium to form uranium:deuteride, stopcock -2-l is-cIOsedthe-reby shutting off reactionchamber 22 from the remainder -of the system, and previously prepareddeuterium ispadmitted under pressurefrom a deuterium sup- ;ply chamber,notshown, .to reaction chamber '22 through supply tube 31 by openingstopcock 32.

,Reaction chamber l-z containing massive uranimetal in the .form ofturnings or other convenient form presenting a ,large surface "area isheated byifurnace 24 to a favorable temperature .for. the reactionbetween :the uranium and deuterium, as, for example, between 200 .C. and400 C. In general, the reaction ,proceeds more rapidly as thetemperatureand pressure of reaction chamber .22 is increased, thepressure of reaction chamber 22 being automatically controlled by therate of generationof the deuterium-in the closed system.

In carrying out the process in which .zgaseous deuterium is prepared inthe system .and then reacted withuranium, stopcock '6 'isclosed,wsto.pcocks 12.1 and, (29 are opened, and the system .isevacuated through-exhaust tubal-8. vAfter asufat a suitable temperature,such as between 600 C..

and 800 0., for the reduction of the deuteride oxide vapor. The gaseousdeuterium resulting from the reduction of the deuterium oxide in thereduction chamber passes through tube l4 into the-trap in whichdeuterium oxide vapor carried by the deuterium is condensed and removed.,,The dried deuterium is conveyed by tube [9 from the trap into reactionchamber 22, maintained at a suitable temperature by furnace 24, in whichthe deuterium reacts with metallic uranium 23. to form uraniumdeuteride. Reaction chamber 22 is preferably maintained at a temperaturesimilar to that maintained in reaction chamber 22 when previouslyprepared deuterium is reacted with uranium, such temperature being, forexample, between 150 C. and 400 C. As the reaction takes place, theuranium deuteride tends to fall away from the uranium metal therebyexposing additional. uranium metal for further reaction. The reactioncontinues until all of the uranium is converted to uranium deuteride. Ata temperature of 300 C. in reaction chamber 22, 100 grams. of uraniumturnings have been converted -to uranium deuteride in less than thirtyminutes and a 100 gram lump of uranium metal has been converted touranium deuteride in less than two hours.

After conversion of the uranium metal to uranium deuteride issubstantially completed, the pressure in the system increases rapidly asthe supply of deuterium to the system continues, such increased pressurein the system being visibly indicated by manometer 33. stopcock 2| isthen closed to seal oif reaction chamber'ZZ from the remainder of thesystem and to permit removal of the uranium deuteride. Stopcock 6 isalso closed to prevent further generation of deuterium in reductionchamber 8. The uranium deuteride is preferably partially cooled in theatmosphere of ga'seous deuterium present in reaction chamber 22 in orderto prevent orminimize thermal decomposition of the deuteride at the endof the reaction. Where stopcock 2| is not provided, reduction chamber 8should be maintained at a lower temperature than that of reactionchamber 22 during the cooling of the uranium deuteride to preventdistillation of deuterium from reaction chamber 22 to'reduction chamber8 and the consequent decomposition of the uranium deuteride duringcooling.

The pressure established in reaction chamber 22 during hydrogenation andcooling is maintained at or somewhat above the decomposition pressure ofthe uranium deuteride. Thus where a temperature of approximately 300 C.is maintained in the reaction chamber, the decomposition pressure of theuranium deuteride is approximately 27 millimeters and the uraniumdeuteride formed will decompose at this temperature into deuterium anduranium metal whenever the deuterium pressure falls below this value.Continued introduction of deuterium into the reaction chamber tends to"increase the pressure until it exceeds the decomposition pressure,thereby causing formation of uranium deuteride. As the deuteriumcombines with the uranium, the pressure in the reaction chamber tends todecrease and if the pressure goes below the her increases the proceeds.

This afiords a simple and efiective means forcontrolling the r-ate ofdeuteride formation and for determining the time at which the reactioniscom-pleted. Thus,

cess of the decomposition pressure but insufilc1en=t to cause thehydrogenation-reaction to"oc'-- our more or less explosively. Usually apressure which is not over the decomposition pressure is established. In

general deuterium is introduced substantially as and at a ratesufiiclent rapidly as it is consumed to replace consumed hydrogen and tomaintain thedeuterium pressure peratur-e.

After the reaction has been completed, thedeuterium introduced causesthe pressure-to"-in- Ewample 2016 grams of powdered uraniumtetrafluoride having a particle size such that per centpasses a 60 meshscreen, 85 per cent passes an 80 mesh screen and 50 per cent passes a200 mesh 7 was mixed with 400 grams of metallic magnesium having aparticle size of about 20 mesh, the charge packed in an iron cruciblelined with calcium oxide and the crucible closed. The crucible wasgradually heated until it reached an outside ternperature of about 640C. Molten metallic ura-" nium and magnesium fluoride formed anduthetemperature of the mixture was maintained sufficiently high to retaintheuran'ium in molten state until the uranium and themagnesiumjffiuoride separated into separate layers wherebyupon coolingmassive uranium having a melting point of 1100 C.25 and a density of19-01 grams per cubic centimeter was secured.

This uranium was formed into turnings and was placed in reaction chamber2 2 1,00fgra ms of uranium metal, also in thef-orm of turning's, wereplaced in reaction chamber 8. Flask 3 was partially filled withdeuterium oxide concentrate} containing 99' per cent by weight of D'Qfand; water bath 4 heated to approximately 30 CfRe ceptacle l5 Wasfilled with dry ice and acetone. With stopcock 6 closed and stopcocks 2|and 25 decomposition pressure. the formation of uranium deuteride isretarded until" further supply of deuterium to the reaction sham-1pressure above the decomposi= tion pressure whereupon deuterideformation:

at the start of the reaction:- deuter-ium is supplied to chamber 22 inan amount: sufficient to establish a deuterium pressure in ex aboutmillimeters 1 "above within the system -.-above. the decompositionpressure at the reaction'tem-f pressure increase will be:

it is necessary to pre pare the deuteride from a composition in whichscreen o en, an vac-um. of: the atria of, .r millimeter: wastobtained;the system by; evacuating means attacheditn ontlettuhez Zll .v stopcock;28: was then; closed;.. reaction chamber? 8:. heated to. approxis- 700G2; and: reaction: chamhenrm. heated; to approximately 250 C. by furnace24.. There;- coclc &- was. opened: and. deuterium oxide vapor: deliveredto chamber 8 ion deuterium. formation; and; the process conducted. as.previouslydescribed. The conversions oi' uraniumto urae niumdeuterldewaszsubstanti ally complete inz-two and aha'lfihoursathe completion;being indicated by: manometer-""33; stopcock was closed, theapparatuscooledzand disassembled, and. the uraniumadeuteride in the;amount. of. 102.54 grams. WEIS-"IQmDYBd.

Uranium; deuteride is. a black; powder which has been: found to he a;convenient means of storing or handlingdeuterium. in a form: from.Whiflhl the deuterium canbe made readily.- availahle;-as;a. pure gas.One gram mole of. uranium deuteride oia bulk densityfromv 35130, 4; thatis, 60 to 80 cubic centimeters of the compound conztains approximately35- liters, of deuterium at atmospheric; pressure; Deuterium in. gaseousform: is released: from; the: uraniumdeuteride by heating the; compoundabove its decomposition temperatureatathe existing pressure.

The approximatedecomposition temperature of the: uranlmndeuteride atvarious pressures, in millimeters; of mercury is given in the followingtablet.

Uranium Uranium Deuteride Hydride Decomposition Decomposition PressurePressure mm; of Hg' m-n1 of g.

The term uranium as used in the following claims is intended to includemetallic uranium, physical mixtures. of uranium with othermateri-alssuch as. tin or other metallic. dendrites, and alloys in whichuranium is the predominantconstituent...

The above detailed description is for purposes of; illustrationand theinvention is to.-be limited only by. thescope. of the-following. claims.

Eris-application is generally related to my copending applicatiomserialNo. 546,178, filed July 22, 1344-,- now Patent No. 2,446,780dated-August 10; 1948, which. is directed to aprocess ofpreparinguranium hydride.

What is.claimediis:

LThe process of preparing uranium deuter me. which. comprises reducing.deuterium oxide in a closed. system tov obtain. gaseous deuterium andthen reacting the deuterium with uranium insaid system. I

2. Theprocess of preparing uranium. deuteride which comprises passingdeuterium. oxide. vapor overa reducing agent in afirstreactionzone toobtain gaseous deuterium. and then. passing the generated deuterium overuranium ina second reaction zone Whichis in. intercommunication with.thefirst' reaction zone.

3. Thevprocess of: preparing uraniunrdeuteridw which. comprises.introducing. a composition in" which. the preponderant aqueous.compound: is

deuteriumzoxide. into a closedsystem generating deuterium oxidevapor ata. constant rate in said deuterium oxide vapor and a reducing agent inrafirstreaction zone in sald system: at. atemperature sufficient to reducethe deuterium oxide vapor to gaseous deuterium;

system, reacting said and thenreacting the deuterium ith uranium imanother? reactionxzone in said system at'. a temperature between C..andAOflf" C;

4.-.. The process of preparing: uranium deuteride which comprisesvintroducing a:. composition inwhich; thev preponiderant aqueous compoundis deuterium oxidein-tow a closed: system generat ing deuterium: oxidevapor at: a. constant rate-1m said system, reacting-said deuteriumoxide-yawn: anda reducing agent. in a first. reactionazone atsatemperature sufficient. to reduce the deuteriumi oxide vapor to'gaseous'deuterium, dehumidifying: the. deuterium. and; then, reacting: the.deutenium with-uranium in saidsystem.

5. The process of obtaining. uranium. deuterid'e. which comprisesintroducing deuterium; oxide in a closed system generatingdeuteriumoxide vapor at a constant rate in saidsystem, reducingsaim deuteriumoxide vaporto'gaseous; deuterium at' ai constant rate and passing thegaseous deuterium into contact with uranium at" a temperature-he tween150 C. and 400 C. in saidssystem..

6. The process of preparing uranium deuteride" which comprisesgenerating. gaseous deutertumnim aclosed system, reacting-the deuteriumsubstan.-- tially as rapidly as formed with uranium in said system, andvisually indicating the: gaszpressure within the; system whereby anincrease in said: pressure indicates the completion. of the reaction:betweenth'e deuterium and the uranium;

'Z. A. method of preparing uraniun'r deuteridewhich comprisesintroducing: a. composition. in: which. thepreponderant. liquid aqueous;compo?- nentv is deuterium oxide intoa CIOSGdiSYStEIIlLhK-Yr ing. threezones communicating in; series, introe ducing a reducing metal into thesecond; zone and uraniumv metal. into the third zone,..heatinzi thedeuterium oxide whereby deuteriumoxide: Val por is.generated and. forcedinto-the second: zone; heating. the. second zone tocause:interactionaofl the reducing metal. with thevapor and generate:deuterium gas which is torced bythe incoming vapor into the. third zoneand heatingthe'thirrh zone toreact the deuteriumwith the uranium..

AMOS S. NEWTQN.

REEEBENCESv CITED.

The following: references. are of; record in the file of this patent:

UNITED; STATES PATENTS.

Number Name Date- 1,816,830 Driggs Aug. 4,1931"- 1,835,024- Driggs Dec.8; 1931 2,156,851-

Hansgirg. May 2, 1939 OTHER REFERENCES Certificate of Correction PatentNo. 2,452,139. October 26, 1948.

AMOS S. NEWTON It is hereby certified that error appears in the printedspecification of the above numbered patent requiring correction asfollows:

Column 6, line 66, for 1100 C.25 and a density of 19-0.1 grams read 1100C'.i25 and a density of 19:1;01 grams,

and that the said Letters Patent should be read with this correctiontherein that the same may conform to the record of the case in thePatent Ofice.

Signed and sealed this 5th day of July, A. D. 1949.

THOMAS F. MURPHY,

Assistant Uommz'ssioner of Patents.

I Certificate of Correction Patent No. 2,452,139.

AMOS S. NEWTON It is hereby certified that error a ppears in the printedspecification of the above numbered patent requiring correction asfollows:

Column 6, line 66, for 1100 C.-25 and a density of 190.1 grams read 11000.:b25 and a density of 1-9;l;0.1 grams;

THOMAS F. MURPHY,

Assistant G'ommieaz'oner of Patents.

October 26, 1948.

